The letter had come from an unknown mischief-maker.

这封信来自一个匿名的离间者。

《柯林斯英汉双解大词典》

Lamp-Wick was the laziest boy in the school and the biggest mischief-maker, but Pinocchio loved him dearly.

蜡烛芯是学校里最懒的孩子，也是最大的捣蛋鬼，但是皮诺乔很喜爱他。

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She was on her neighbor's property now, and she doubted the reclusive older man would welcome either her or her four-legged mischief maker, so she forged onward.

海利现在到了邻居家的地盘上，但她觉得这个深居简出的老人不会欢迎她和她那顽皮的四条腿朋友，所以她继续往前走。

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But it was Hagman, as the city's chief mischief-maker, that would make the bigger impact.

BBC: Obituary: Larry Hagman

Although the Pune police said the blasts appeared to be the work of a "mischief-maker", federal authorities said a terror attack could not be ruled out.

BBC: India: Pune blasts 'planned and coordinated'